Nanako is a little girl with brown hair, short pigtails and brown eyes. Normally, she is seen wearing a white turtleneck under a sleeveless dress in pink and two shades of red, white socks and pink shoes. In summer, however, she wears a light pink dress. Along with the rest of the girls, Nanako sports a kimono at the summer festival.

Despite never being seen without her pigtails in Persona 4, Persona 4 The Animation depicts Nanako with her hair down while sleeping, and also revealed that she had her hair shoulder length.

In the new true ending in Persona 4 Golden she is shown with longer hair.

Nanako is a mature and kind person for a girl her age. She is quite responsible and reliable, and has handled a lot of housework, such as cooking and laundry in her home ever since her mother passed away. She loves Junes, in both its slogan and in visiting their Inaba branch with her family and friends. She tends to be shy around strangers, but adores spending quality time with her father and cousin whenever possible. As she develops more trust in her older cousin, she begins calling him "Big Brother"/"onii-chan" as if he really was her older brother. After becoming more acquainted with his friends, she also begins add the "onii"/"onee" honorific at the end of their names, except for Teddie (i.e. Chie-oneechan, Yosuke-oniichan, etc.). However, this only takes place in the Japanese version, as in the English version Nanako simply refers to them by their names.

Nanako lives with her father Ryotaro Dojima, a detective in Inaba, at the Dojima Residence. Her mother died in a hit and run when she was young, and thus all the household chores fall to her, but despite her age she does an admirable job managing both the cooking and cleaning after school. Nanako can usually be found in the living room watching television, and is especially absorbed in quiz shows. Nanako is a big fan of the Junes Department Store, singing along with the jingle every time a commercial airs. When Ryotaro suggests they go on an outing, Nanako suggests they all go to Junes, instead of taking a vacation. Nanako represents the Justice ArcanaSocial Link, which she creates with the protagonist should his 'Expression' characteristics reach a sufficient level. As the protagonist interacts with her, he helps Nanako understand her father, and helps to mend their strained and distant relationship.

She's very mature and independent for her age; Dojima notes her resemblance to his late wife, Chisato, in both personality and appearance. Nanako distanced herself with the protagonist at first, but grew much closer to him as her Social Link progressed. When her Social Link is maxed, and the player chooses to talk to her, she will always proclaim her love for him. Nanako is a big fan of both Rise Kujikawa, and the fake "Risette." Many characters have been inspired by her bravery, and all of them have shown great sorrow and regret for not being able to prevent her abduction. Although she harbors a great love for her father, she sometimes questions his love for both her and Chisato.

Late in the game, a political figure visits Yasoinaba. While there, he visits Nanako's school, where he surveys the students about their worries, and the worsening occurrences of fog. Nanako gives the politician an innocent yet genuine answer, which later makes the local TV news. However, her image is not shown on television; only her quotes and vague details about her were mentioned.

A few days later, when Dojima intercepts a second warning letter left in the Dojimas' mailbox, he angrily brings the protagonist to the police department for questioning, and leaves Nanako home alone. Eventually, he leaves his nephew detained at the station, confiscates his phone, and leaves him under Adachi's watch. The Investigation Team is unaware of what has happened — only when Yosuke and Teddie idly call the protagonist on his cell and home line do they find out from Nanako about the situation. Worse, only a short time later when the Midnight Channel airs, Nanako is revealed to be the next victim.

Nanako is seen clearly on the Midnight Channel

Realizing that Nanako is in danger, the Investigation Team leaps into action, half of them heading for the police station to talk the protagonist out of detainment, and the remainder to the Dojimas' to check on Nanako. Along the way, Naoto Shirogane explains how Nanako's image could have appeared on the Midnight Channel despite never having become famous on TV: days after the news report, the newspaper published Nanako's photo and information while covering the same story. With a face to match to the popular news piece, the murderer had secured his next victim.

Amongst the confusion, and before the Investigation Team can interfere, Nanako is kidnapped. In the police station, gathering the salvaged bits of clues Ryotaro Dojima managed to collect relating to the initial two murders, the Investigation Team eventually deduces the culprit's identity and method: Namatame, council secretary and lover of the first victim Mayumi Yamano, and whom now works for his father's delivery business. Ryotaro takes off in his SUV in pursuit of the kidnapper's delivery truck, causing Namatame to panic at the wheel — the truck spins out, Ryotaro loses control, and both vehicles crash into the façade of a nearby building. Luckily, the Investigation Team is not far behind and Ryotaro is quickly attended to by an ambulance, but the kidnapper and his victim are nowhere to be found. Finding a large TV in the back of the delivery truck and a diary listing information regarding all the victims thus far, the Investigation Team affirms their theory and plan Nanako's rescue, and Namatame's pursuit.

Inside the Midnight Channel, Nanako's presence creates her reality, Heaven, which reflects her innocence and her wish to see her mother, whom Nanako believed to be in Heaven after her death. Working their way toward her, Rise asserts that Nanako is not the only person trapped inside this reality; they realize with horror that Namatame didn't throw in his victim and escape, but instead that he followed Nanako inside to escape the police. The Investigation Team eventually makes it to the top, where they find Nanako being held hostage by Namatame. Due to Nanako's age, innocence, and lack of emotional baggage that would generate a Shadow, her own does not emerge … but Namatame's is revealed to be one and the same with his own form, and this bizarre human-shadow fusion produces a Shadow creature of terrifying power that the team manages to defeat. Though Namatame is subdued, Nanako seems to have fallen strangely ill, and passes out in the protagonist's arms.

After the police arrive to apprehend Namatame and rush the young girl to the hospital, Nanako eventually awakens. The doctor, however, is perplexed and admits to a worried Dojima that they cannot actually identify what is wrong with her, and are just numbing her current pains with medication as well as they can. Teddie expresses concern that Nanako spent too much time in the TV world, and that the fog must not have been good for her, to the Investigation Team's chagrin.

Days later, while out with the team buying Nanako a Christmas present, the protagonist gets an urgent call from Adachi telling him that Nanako's condition suddenly became critical. The Team rushes to Tatsumi Memorial, but despite the doctor's efforts, Nanako quietly slips away, calling out weakly to her father. Stricken, Dojima runs to Namatame's room, but is later escorted by the police guard back to his room, giving the Investigation Team the opportunity to sneak in. Grief-ridden and devastated, and convinced on Naoto's word that it's likely the court will never find him guilty, the Investigation Team contemplates bringing Namatame to justice by pushing him through his hospital room's TV. This decision turns out to be crucial, as can be seen in the ending threads below.

Should the protagonist choose to kill Namatame to avenge Nanako, the game ends with her death, and Ryotaro grieves over being unable to see her one last time. Teddie returns to the Midnight Channel, leaving the Investigation Team a note, and the case goes unsolved. The stifling fog is never lifted, and the game ends on a bitter note with the protagonist departing Inaba to return to the city.

The 'neutral' ending can be unlocked should the protagonist choose to talk the Investigation Team down and spare Namatame, but then fail to identify the real culprit. Teddie then returns to the Midnight Channel, leaving the Investigation Team a note. Nanako is revived, although she remains in a coma, the stifling fog is never lifted, and the case goes unsolved. The 'neutral' ending fast-forwards to spring of the next year, during which Ryotaro Dojima takes the protagonist to the train station to head back home to his parents, lamenting that it was too bad Nanako wasn't yet healthy enough to leave the hospital and see him off.

Should the protagonist talk the Investigation Team down and spare Namatame, expressing his doubts that it would solve the case of the bizarre murders, Nanako will be revived. The Investigation Team will discuss the case further and deduce that there may, in fact, be a second murderer involved, whom they must track down. After the case is finally solved and the true culprit apprehended, Nanako is released from the hospital and is able to spend Christmas with her father, cousin, and the Team. By the time the protagonist has to return to the city in the spring, Nanako is back to full health and cheerfully sees him off.

Upon the Investigation Team's realization that a last player in the bizarre murders must be eliminated, the protagonist needs Nanako's help to remember a certain individual he met on his first day in Inaba. Nanako recalls stopping at the Moel gas station on their way from picking him up, and this small detail helps the Team track down the gas station attendant Izanami.

In the anime, when she receives a gift from her father on May 5th, it is a blue shirt with a picture of a platypus instead of an orange one like in the original game.

On July 10th, when she is out shopping at the market, she encounters Mitsuo. He attempts to grab her, frightening her, but Yu intervenes.

At the Dojima household, after they defeat Shadow Mitsuo and catch the original, the group hangs out with Nanako. Each of the girls make horrible food that Nanako eats, and says nice things about in order to cheer them up. She then makes a pinky promise with Teddie and notices that Yosuke calls her "big bro" by his name, Yu.

On August 8th, she encounters the Fox while it is raining. She gives it her umbrella, to which it expresses its gratitude. While at home with Yu, she notices that he's been very busy lately, and hasn't been spending as much time with her. Thus, in the following days, she wears her superhero outfit to investigate Yu's whereabouts. As Nanako continues spying on Yu, Teddie interrupts her and sniffs out Yu's scent. He tells her Yu's location, and in spite of being aware the information is false, she chooses to follow him anyway to a food shop. The next day, she continues to look for him with the help of Yu's friends. They continue the search, but are ready to give up. That is until they see "Teddie" take a bus and begin questioning him until he runs away from them.

On August 18th, she finally finds Yu, catching him with an older woman with black hair, and believes he's on a date. While at the Junes Court, sitting disappointed and depressed, she encounters Yosuke and Teddie. She tells them everything about Yu dating older women. Together, along with Kanji, they go to find Yu, and end up discovering him with another older woman. Nanako notes that this is not the same woman she initially saw, which the guys react to in shock. This time with disguises given to the girls by Teddie, notably Yukiko, Chie, and Rise, they continue following Yu and find him with a much older lady. They respond to the discovery with a great deal of shock, remarking together, "He's dating someone's grandma!?!?".

Nanako with Yu watching the fireworks

At the Summer Festival, as she begins to give up and leaves her mirror behind, Naoto appears and gives it back to her. She encourages her, and tells her not to give up until the case is over. Before she can do so, she notices Kou and Daisuke having trouble with their stand, as all their shaved ice has sold out. She helps them by talking to one of Yu's friends, as they have ice at their restaurant and can deliver it. She also helps Ai get her scarf out of the tree with her extended mirror-like stick. She later sees Yu while he is holding something and continues her investigation of him. However, before she can get any further, she stops once again, to help Daidara from choking on his snack. Eventually, she is able to find Yu, and they are able to watch the fireworks together. The boy she saw from yesterday then appears, needing to ask Yu for something. She notices that he is smiling even as he cries. As Nanako meets the people Yu has befriended, during the festival she gets to spend time with her father and "Big Bro" as a family. As the summer comes to an end, she questions Yu on what he's been doing over the summer.

On October 11th, Nanako becomes depressed that her father is at work all the time, and isn't able to spend time with her. Nanako tells Yu that it's like Dojima is not even her real father. Throughout the weekend, she asks her father to sign a form to observe her class at school. When he doesn't, she accuses him of putting his job first and foremost. Later, Nanako overhears Dojima and Yu's conversation about a "hit and run". Nanako confronts Dojima about never listening to her, then repeatedly calls him stupid, tells him he never cares about her, and exclaims, "You're not really my father!", leaving home in tears.

She is later found at Samegawa Flood Plain, where Dojima, Chisato, and she used to have picnics before her mother's untimely death. Nanako starts to cry again, asking why her mother had to leave her, and begins to wonder if her father would do the same. She sobs in her father's arms, and begs for his forgiveness. During the credits, she is glad that her "Big Bro" and her father are now a family.

In November, Nanako is abducted by Namatame and thrown into the TV, where she subsequently creates Heaven. After he merges with his Shadow, Nanako is still caught in his clutches. When the party finally arrives, Yu tries to rush in to save her, but his body becomes controlled by Kunino-sagiri, and is turned against the party. He summons Beelzebub and almost kills the entire party with Megidolaon, but Nanako manages to wake up and pleads with him not to fight them. This prompts Yu to notice the ring she had given him, giving him the strength to resist Kunino-sagiri's control long enough for Tomoe and Take-Mikazuchi to disable the Devil Persona.

Sukuna-Hikona then cuts Nanako free of Kunino-sagiri's grip, but ends up causing her to fall from a great height. Yu manages to gather his strength to break free from Kunino-sagiri's control, and catches her before she hits the ground. His bond with Dojima then gives him the strength to summon the Ultimate Form of the Hierophant Arcana, Kohryu, allowing him to protect Nanako from further harm, and freeing the rest of the party from Kunino-sagiri with Salvation. Nanako later gives him the strength to summon the Ultimate Form of the Justice Arcana, Sraosha, allowing him to purify the remaining Shadows with Mahamaon.

On December 3rd, Nanako dies in the Inaba Municipal Hospital, but later on December 4th, Nanako mysteriously comes back to life much to the relief of everyone there.

After Ameno-sagiri was defeated, she woke up and told her father that she dreamt that Yu and his friends had defeated the "bad guys".

Nanako shows up in the P4 route, where she appears at the beginning and is trying to cook. She is also impressed by how cool Kanji is. She later shows up in the epilogue.

Nanako, along with Marie and theVelvetSiblings, is available as a DLC Navigator for $3. The DLC Navigators do not have additional skills, but can replace Fuuka's or Rise's voice to provide vocal support by selecting them from the "Support" section of the "Party" menu.

In the video game, Nanako receives an orange shirt with a picture of a platypus, but in the anime it's a blue shirt with a platypus.

Nanako is the character that interacts or is involved with the most Social Links. She is a secondary character in her father's Social Link. She spends time with the Investigation Team during a few events. Some Social Links have additional scenes involving Nanako during certain rank-up events if the player attends them before November (these scenes are simply omitted if the player attends them after November). In the anime, she encounters some Social Link people as well (Fox, Ai, Hisano, Sayoko, Eri, Shu). She also has a few appearances in the new Social Links included in Persona 4 Golden.

In final episode of Persona 4: The Animation, she told Yu that she was going to marry him someday. Her feelings and actions are similar to Maiko at the end of her social link with protagonist in Persona 3.

Her birthday, October 4th, is the same day that Ken Amada's mother and Shinjiro Aragaki, both from Persona 3, died. Ken Amada and Nanako are also both Justice Social Links.

This could be a coincidence, as she died in the Bad Ending of the game, though in the Good Ending she makes a recovery.

Nanako's starsign is Libra, depicting scales and the Justice Arcana, her Social Link, also depicts scales on it.

In Persona 4 Arena Ultimax, there is a color variation DLC for Yu Narukami which is based on Nanako's clothes (pink and red).